Before starting that diet, consider its effect on your gut

Each year about 45 million Americans go on a diet, but many have no idea that they could be changing their microbiome in the process. While some of the changes can be beneficial, other changes in your gut environment brought about by fad diets can hinder long term efforts to lose weight and result in serious health consequences.

“The bacteria that reside in your intestines are important for day to day function but also for your overall health,” said William DePaolo, a UW Medicine microbiome expert and director of the Center for Microbiome Research and Therapeutics.

“Every time you diet, it’s causing fluctuations in the compositions of your gut bacteria and basically destabilizing that community,” DePaolo said.

The changes in what you eat can have positive or negative consequences to your overall health, he said. A healthy and varied diet – one high in fiber, fruits, vegetables and lean meats – is generally considered good for your gut. Fad diets, which focus on one food group or which eliminate variety in the diet, generally have a negative effect on the microbiome and potentially, your long-term health, he said. In short, you are what you eat. Especially in your gut.

“If you change your diet,” DePaolo said, “some of the consequences of that is bacteria now express different genes that could predispose an individual to inflammation that could cause serious health consequences or long-term chronic disease.”

Studies on diets and the microbiome have indicated that the microbiome changes rapidly with the addition, or subtraction of foods, and what you eat, through your microbiome, can affect whether you are prone to asthma, irritable bowel disease or even some forms of cancer.

Generally, DePaolo favors diets which are varied and high in fiber, which includes fruits, vegetables, whole grains, nuts and seeds. The FDA recommends that individuals consume more than 25 grams of fiber a day. According to FDA studies, the average American consumes only 15 grams of fiber a day.

If you wonder what 25 grams translates into in terms of food, that is five large apples or oranges, eight medium bananas or seven cups of blueberries. Legumes, including beans, peas and lentils, are particularly fiber-rich — lentils provide about 5 grams of fiber per half-cup.

For more on diets and the microbiome, here is a downloadable video interview the DePaolo.

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